The present invention relates to computer software for use with a disk operating system, and more particularly to a program for inhibiting use of executable programs in a disk operating system.
Executable programs are programs in the disk operating system (DOS) loaded in a computer and are initiated with external commands by the computer operator. In Microsoft.TM. or IBM.TM. DOS, these programs are identified by discrete filenames with extensions COM, EXE and BAT. Programs with extensions COM and EXE, take precedence in execution over the same filename with a BAT extension. Two such programs are FORMAT.COM or FORMAT.EXE for initializing a new, unused disk, and DISKCOPY.COM or DISKCOPY.EXE for copying everything from one disk to another.
There are times, however, when it is desired to prevent such executable programs from being used. For instance, before a new or blank floppy or disk can receive and store information in binary form, it must be initialized or formatted with special markers so that when an executive or operating system reads or writes a file to the disk, it will know on which sector and track the file is written. Formatting also sets up directories containing file location information and checks the disk for defects. Once the disk is formatted, information can be stored on it as often as desired without reformatting. To prevent a user from writing over previously recorded information, the sleeve which contains the floppy or disk usually has a small rectangular notch or window on one side. If the notch or window is covered when inserted in a disk drive, the computer prevents information from being written on the disks. Most master distribution disk for software products have no notch and are therefore permanently write-protected. However, write-protection will not protect against formatting. Formatting will permanently wipe off the entire contents of any previously created operating systems and recorded information on the disk. Therefore, a user must always be consciously aware of the consequences of formatting any disk media, particularly a fixed disk, and be absolutely certain it contains no files which need to be retained.
While the consequences of accidentally or maliciously executing a formatting program are especially severe, other programs are similarly vulnerable. For instance, there is no means within a DOS for preventing a user from executing the external command DISKCOPY and making an unauthorized copy of confidential information recorded on another disk such as the fixed or hard disk of a computer.